Hi Spaceman,
see
http://wonkity.com/~wblock/SCSI/SCSIExamples.html"It seems that the SCSI bus is one of the most misunderstood aspects of connecting hard drives and other peripherals to the A4000 (or, for that matter, any other Amiga model). This section of the guide is an attempt to provide some simple examples of proper SCSI device connections. Please note that in the following section, and in the Guide as a whole, I have used the common term controller when referring to disk adapter boards, although the more accurate description for both SCSI and IDE would be "host adapter."
Regards, Michael
aka rockape